1. Field of the Invention
This invention relates to an extraction cleaning machine and, more particularly, to an upright extraction cleaning machine. In one of its aspects, the invention relates to a self-propelled extraction cleaning machine. In another of its aspects, the invention relates to a self-propelled extraction cleaning machine with dirt sensing. In another of its aspects, the invention relates to an extraction cleaning machine in which the degree of a cleaning function is controlled by the amount of dirt in the carpet.
2. Description of Related Art
Upright extraction cleaning machines have been used for removing dirt from surfaces such as carpeting, upholstery, drapes and the like. The known extraction cleaning machines can be in the form of a canister-type unit as disclosed in U.S. Pat. No. 5,237,720 or an upright unit as disclosed in U.S. Pat. No. 5,867,861.
Current upright extraction cleaning machines can be made easier to use by limiting the weight and number of components, such as fluid storage tanks, on the pivoting handle of the upright cleaning machine. Reducing the weight that a user must support as the handle is tilted rearwardly can also lower the center of gravity for the machine, which results in a better feel to the user. The degree of cleaning depends on a number of factors, including the speed of the machine along the surface to be cleaned, the relative amounts of cleaning solution and water, the amount of soil in the carpet or surface, the amount of suction applied to remove the dirty fluid from the carpet or other surface and the temperature of the cleaning fluid. The use of an agitator, if any, and the speed and pressure of the agitator will also affect the cleaning of the carpet. These factors are generally not controlled with respect to the carpet or floor condition although on some machines, the relative amounts of cleaning solution and water can be manually adjusted by the operator. However, the operator does not have any scientific way to judge the amount of soil in the carpet and simply does a visual guess as to the condition of the carpet and adjusts the amount of cleaning solution in the mix. Further, the speed of the extractor along the carpet or other surface depends on the operator. Thus, the rate of cleaning will likely vary by operator.
According to the invention, an extraction surface cleaning apparatus having a housing, at least two wheels mounted to the housing for supporting the housing for movement along a surface to be cleaned, a liquid dispensing system mounted to the housing, a fluid recovery system mounted to the housing, and a vacuum source. The liquid dispensing system includes a liquid dispensing nozzle for applying liquid to a surface to be cleaned, a fluid supply chamber for holding a supply of cleaning fluid, and a fluid supply conduit fluidly connected to the fluid supply chamber and to the dispensing nozzle for supplying fluid to the dispensing nozzle. The recovery system includes a recovery chamber for holding recovered fluid, a suction nozzle, and a working air conduit extending between the recovery chamber and the suction nozzle. The vacuum source is in fluid communication with the recovery chamber for generating a flow of working air from the suction nozzle through the working air conduit and through the recovery chamber to thereby draw dirty liquid from the surface to be cleaned through the suction nozzle and the working air conduit, and into the recovery chamber. The apparatus further comprises a variable cleaning control element mounted on the housing and adjustable to control the rate of cleaning by the extraction surface cleaning apparatus, and a sensor for detecting a condition of the surface to the cleaned and for generating a condition signal representative of the detected condition of the surface to be cleaned.
In one embodiment, a controller is operably coupled to the sensor and to the variable cleaning control element. The controller is programmed to control the variable cleaning control element in accordance with the detected condition of the surface to be cleaned. The detected condition can be related to the degree of soil in the surface to be cleaned and the condition signal is a soil-degree signal. In one embodiment, the controller includes a data structure having data representative of various degrees of soil in the surface and control settings on the variable cleaning control element. The controller is programmed to compare the soil degree signal with the data representative of various degrees of soil in the surface to be cleaned (or being cleaned) and for generating a control signal to the variable cleaning control element to adjust the degree of cleaning of the extraction surface cleaning apparatus to match the detected degree of soil in the surface to be cleaned.
In one embodiment, the variable cleaning control element is a motor operably connected to the wheels for driving the wheels and powering the housing along the surface to be cleaned. In this embodiment, the variable cleaning control element is a speed control component for controlling the rotational speed of the wheels. In a further embodiment, the motor is a variable speed motor operably connected to the wheels for driving the wheels and powering the housing along the surface to be cleaned. The speed control component controls the speed of the motor and thus the rotational speed of the wheels and the speed of the extractor along the surface being cleaned.
In a further embodiment, the fluid supply chamber comprises a first tank for concentrated cleaning solution, a second tank for water, a mixing valve for adjusting the relative amounts of concentrated cleaning solution and water, and conduits between the first and second tanks and the mixing valve. In this embodiment, the variable cleaning control element is the mixing valve.
In a further embodiment, the sensor detects the soil degree condition by measuring a characteristic of the surface to be cleaned, or, in the alternative measures a property of the recovered fluid. The sensor can be positioned to detect the condition of the fluid in the working conduit, or in the recovery chamber. The property of the recovered fluid can include relative degree of dirt in the recovered fluid or the relative amounts of foam in the recovery chamber.
The sensor preferably comprises a photocell for detecting light level transmitted through or reflected by the surface or the fluid, and can include a light source. The sensor can also comprise a conductivity sensor.
In a further embodiment, the controller is operably coupled to the sensor and to the variable cleaning control element to control the variable cleaning control element in accordance with the detected condition of the surface to be cleaned. The the controller includes a data structure having data representative of various degrees of soil in the surface and control settings on the variable cleaning control element. The data structure includes data representative of the light intensity value of the cleaning fluid and the controller includes a spectral comparator for comparing the light intensity value of the recovered fluid to the light intensity value of the cleaning fluid. The light intensity value can be a predetermined value. Alternatively, a sensor on the housing detects the color of the cleaning fluid in the fluid supply conduit and generates a signal representative of the detected color which in turn forms the data representative of the light intensity value of the cleaning fluid.
The condition being detected by the sensor can further include a concentration of a chemical component of the recovered fluid. The component can be a compound in the cleaning fluid that is modified by the soil level in the recovered fluid.
In a further embodiment, the sensor comprises a reflectance sensor directed at the surface being cleaned to sense the degree of soil in the surface.
In a still further embodiment, the an indicator is mounted to the housing and coupled to the sensor to indicate to an operator the detected condition of the relative degree of soil in the surface to be cleaned.
In yet another embodiment, the controller is operably coupled to the sensor and to the variable cleaning control element, and the controller has a memory with a first stored reference value representative of a desired clean floor condition. The controller is further programmed to compare the soil degree signal with the first stored reference value and for applying a control signal to the variable cleaning control elements until the soil degree signal is within a predetermined threshold of the first stored reference value.
Further, the controller can include a learning mode, an active mode and a manual switch for converting the controller from the learning mode to the active mode and vice versa. The controller is programmed so that the soil degree signal is the first stored reference value when the controller is in the learning mode, and, when the controller is in the active mode, the soil degree signal is compared with the first reference value to control the variable cleaning control element in accordance with the detected condition of the surface to be cleaned. In this manner, a user can place the controller in the learning mode via the manual switch and operate the extractor over a clean floor surface to set the first reference value, and then manually switch to the active mode and operate the extraction surface cleaning apparatus on a dirty floor surface.
The sensor can further comprise a moisture sensor positioned to detect the level of moisture in the surface to be cleaned. The detected moisture sensor signal is used to control the level of extraction of the extractor, either manually or automatically by a controller.
In further embodiments, the apparatus further comprises an in-line heater in the fluid supply conduit for heating the cleaning fluid, and a variable electrical supply to the in-line heater, wherein the variable cleaning control element comprises the variable electrical supply.
In a further embodiment, the variable cleaning control element is a variable-flow fluid pump in the fluid supply conduit.
In a further embodiment, the variable cleaning control element is a variable-speed motor configured to vary the suction in the vacuum source.
In a further embodiment, an agitator for agitating the surface to be cleaned is mounted on the housing and a height-adjustment mechanism mounts the agitator to the housing at various heights with respect to the surface to be cleaned. The variable surface control element comprises the height-adjustment mechanism. In a further embodiment, the variable cleaning control element is a variable pressure application mechanism which is controlled to apply a variable degree of pressure to the agitator. In a further embodiment, the variable cleaning control element comprise a variable-speed motor for driving the agitator.
In a further embodiment, at least one booster tank is mounted on the housing for holding at least one of a booster and oxidizing agent, a mixing valve is connected to the at least one booster tank and to the cleaning solution tank for adjusting the relative amounts of booster or oxidizing agent and cleaning solution to the nozzles. The variable cleaning control element is the mixing valve in this embodiment.
In a still further embodiment, multiple variable cleaning control elements are mounted on the housing and are adjustable to control the degree of cleaning by the extractor. The controller is programmed to control each of the multiple variable cleaning control elements either singularly or multiply. The controller can have manual controls for at least some of the multiple cleaning control elements for manual selection or control of one or more of the cleaning control elements. The multiple cleaning control elements can include at least one of steam, solution concentration, speed along the surface to be cleaned, power to the vacuum source and pressure, height or speed of an agitator.
In a further embodiment, an audible or visual indicator is coupled to the sensor and adapted to indicate the relative degree of soil in the surface to be cleaned to an operator. A manual control is mounted on the housing for varying the cleaning control element by the operator in response to the indicator signal.
In a further embodiment, a sensor detects a condition relative to the degree of cleaning by the extraction surface cleaning apparatus; and an audible or visual indicator coupled to the sensor and adapted to indicate the condition relative to the selected degree of cleaning by the extraction surface cleaning apparatus. In one embodiment, the condition relative to the degree of cleaning is the speed of the extractor over the surface to be cleaned. In an alternative embodiment, the condition relative to the degree of cleaning is a property of the recovered fluid.
In a further embodiment, a sensor detects a condition relative to the level of moisture in the surface being cleaned and is adapted to generate a moisture level signal representative of the detected condition of the relative degree of moisture in the surface being cleaned. An audible or visual indicator is coupled to the sensor and adapted to indicate the relative moisture level in the surface being cleaned. A manual control is connected to the variable cleaning control element for varying the cleaning control element by the operator.
In yet another embodiment, a detector senses the speed of the housing across the surface being cleaned and generate a speed signal representative. An output device is mounted on the housing and is coupled to the detector for displaying or audibly expressing the relative speed of the housing across the floor being cleaned. For example, the detector could be a magnetic sensor on the wheels to detect the rotational speed of the wheels and the output device could be a speedometer with an analog output and which has a graphic relating the speed of the extractor to the degree of cleanability of the extractor so that the operator can adjust the speed of the extractor to the condition of the carpet or other surface being cleaned.